This invention is generally in the field of methods and devices for the delivery of electrical signals to neural tissues in a medical patient in combination with the delivery of one or more drugs to the patient.
Electrical signals from implanted pulse generators have been applied to neural tissues for the control of chronic pain or movement disorders. For example, the delivery of electrical stimulation to the nervous system using an implanted electrode has been found effective in the relief of chest pain, such as angina pectoris, that often accompanies myocardial ischemia. U.S. Pat. No. 5,058,584 to Bourgeois, for example, discloses a system and method for treating chest pain using electrical stimulation within the epidural space of the spinal cord. U.S. Pat. No. 6,058,331 to King discloses a system and method for treating ischemia by automatically adjusting electrical stimulation to the spinal cord, peripheral nerve, or neural tissue ganglia based on a sensed patient condition. U.S. Pat. No. 5,199,428 to Obel et al. discloses a system for stimulating the epidural space with continuous and/or phasic electrical pulses using an implanted pulse generator upon the detection of myocardial ischemia to decrease cardiac workload, and thus reduce cell death associated with the ischemic event. As another example, U.S. Pat. No. 5,824,021 to discloses a system and method for providing spinal cord stimulation to relieve angina, and for notifying the patient that an ischemic event is occurring.
Other publications disclose therapeutic strategies and devices for the delivery of drug by catheters in combination with the use of electrical stimulation. See, e.g., U.S. patent application No. 2002/0013612 A1, U.S. patent application No. 2002/0055761 A1, and U.S. patent application No. 2002/0107553 A1, all of which are incorporated herein by reference.
When applied to control pain, implanted neural stimulators use electrical pulses to block the transmission of pain-related signals through neural tissue. In many cases, however, the neural stimulation is not completely effective in controlling the pain. It would be desirable to provide methods and devices for enhancing the control of chronic pain. When applied to control movement, the implanted neural stimulators use electrical pulses to block the transmission of cortical signals associated with the onset of certain types of seizures or for the control of continuous involuntary movement disorders. It would be desirable to provide methods and devices for enhancing the control of movement disorders. It would also be desirable to provide new devices and methods for the controlled delivery of electrical stimulation in combination with drug delivery for a variety of therapeutic applications.